An electronic device may execute various functions or programs. For example, portable electronic devices such as a smart phone and a tablet PC have been developed to implement advanced performance and give a user convenience. Accordingly, the portable electronic devices have been commonly used.
A portable electronic device is manufactured to be light and in a small size, so that a user can carry and use the device at all times. In addition, most of current portable electronic devices have a touch screen on which a touch panel is mounted. Accordingly, a user can select and use a specific function of a portable electronic device, for example, a specific application through a simple touch input. Furthermore, research has been steadily carried out to improve simplicity of a touch input by a user.
In a case where a user operates an electronic device using his/her one hand, for example, when the user grips the electronic device using one hand and then controls a touch screen placed on the front surface of the electronic device using fingers of the hand which grips the electronic device, there may be an area of the touch screen which cannot be reached by the fingers. For example, as shown in FIGS. 14A and 14B, when the user operates the electronic device using one hand, the user may grip the electronic device in a horizontal direction or a vertical direction. Referring to FIGS. 14A and 14B, the thumb of the hand which grips the electronic device may touch only a partial area of the touch screen. Accordingly, conventionally, when the user operates the electronic device using one hand, the user cannot control an upper area of the touch screen which cannot be reached by his/her fingers.
Conventionally, there has been a technology which controls the front display of the electronic device by touching on the back surface of the electronic device as shown in FIGS. 15A and 15B. However, when the user controls the front display of the electronic device using his/her forefinger or middle finger, positioned on the back surface, due to the limitation of a position to which the forefinger or the middle finger can move on the back surface of the electronic device depending on a size of the electronic device, a partial area of the front display, which cannot be controlled, may exist.